22 research outputs found
Taxonomic revision of Aspergillus section Clavati based on molecular, morphological and physiological data
Aspergillus section Clavati has been revised using
morphology, secondary metabolites, physiological characters and DNA sequences.
Phylogenetic analysis of β-tubulin, ITS and calmodulin sequence data
indicated that Aspergillus section Clavati includes 6
species, A. clavatus (synonyms: A. apicalis, A.
pallidus), A. giganteus, A. rhizopodus, A.
longivesica, Neocarpenteles acanthosporus and A. clavatonanicus.
Neocarpenteles acanthosporus is the only known teleomorph of this
section. The sister genera to Neocarpenteles are Neosartorya
and Dichotomomyces based on sequence data. Species in
Neosartorya and Neocarpenteles have anamorphs with green
conidia and share the production of tryptoquivalins, while
Dichotomomyces was found to be able to produce gliotoxin, which is
also produced by some Neosartorya species, and tryptoquivalines and
tryptoquivalones produced by members of both section Clavati and
Fumigati. All species in section Clavati are alkalitolerant
and acidotolerant and they all have clavate conidial heads. Many species are
coprophilic and produce the effective antibiotic patulin. Members of section
Clavati also produce antafumicin, tryptoquivalines, cytochalasins,
sarcins, dehydrocarolic acid and kotanins (orlandin, desmethylkotanin and
kotanin) in species specific combinations. Another species previously assigned
to section Clavati, A. ingratus is considered a synonym of
Hemicarpenteles paradoxus, which is phylogenetically very distantly
related to Neocarpenteles and section Clavati
Polyphasic taxonomy of Aspergillus section Usti
Aspergillus ustus is a very common species in foods, soil and
indoor environments. Based on chemical, molecular and morphological data,
A. insuetus is separated from A. ustus and revived. A.
insuetus differs from A. ustus in producing drimans and
ophiobolin G and H and not producing ustic acid and austocystins. The
molecular, physiological and morphological data also indicated that another
species, A. keveii sp. nov. is closely related but distinct
from A. insuetus. Aspergillus section Usti sensu
stricto includes 8 species: A. ustus, A. puniceus, A.
granulosus, A. pseudodeflectus, A. calidoustus, A. insuetus and
A. keveii together with Emericella heterothallica
The effect of area and isolation on insular dwarf proboscideans
Aim: We investigated the hypothesis that insular body size of fossil elephants is directly related to isolation and surface area of the focal islands. Location: Palaeo-islands worldwide. Methods: We assembled data on the geographical characteristics (area and isolation) of islands and body size evolution of palaeo-insular species for 22 insular species of fossil elephants across 17 islands. Results: Our results support the generality of the island rule in the sense that all but one of the elephants experienced dwarfism on islands. The smallest islands generally harbour the smallest elephants. We found no support for the hypothesis that body size of elephants declines with island isolation. Body size is weakly and positively correlated with island area for proboscideans as a whole, but more strongly correlated for Stegodontidae when considered separately. Average body size decrease is much higher when competitors are present. Main conclusions: Body size in insular elephants is not significantly correlated with the isolation of an island. Surface area, however, is a significant predictor of body size. The correlation is positive but relatively weak; c. 23% of the variation is explained by surface area. Body size variation seems most strongly influenced by ecological interactions with competitors, possibly followed by time in isolation. Elephants exhibited far more extreme cases of dwarfism than extant insular mammals, which is consistent with the substantially more extended period of deep geological time that the selective pressures could act on these insular populations. © 2016 John Wiley & Sons Lt
The Effects of Business Taxes on Output and Location of the Firm under Uncertainty
[[abstract]]In this article, a triangular production-location model is used to show that when output price is random, the imposition of business taxes (including lump-sum tax, profit tax, output tax, and input tax) can have significant effects on the optimal location and output of a firm attempting to maximize a von Neumann-Morgenstern utility function of profits. In addition, using the concept of differential incidence, the authors also made a comparison of the magnitudes of the impacts of these taxes on the output and location of the firm and indicates that the effects of these taxes differ according to the tax structure.[[journaltype]]國
Phylogeny and Ancient DNA of Sus Provides insights into neolithic expansion in Island Southeast Asia and Oceania
Human settlement of Oceania marked the culmination of a global colonization process that began when humans first left Africa at least 90,000 years ago. The precise origins and dispersal routes of the Austronesian peoples and the associated Lapita culture remain contentious, and numerous disparate models of dispersal (based primarily on linguistic, genetic, and archeological data) have been proposed. Here, through the use of mtDNA from 781 modern and ancient Sus specimens, we provide evidence for an early human-mediated translocation of the Sulawesi warty pig (Sus celebensis) to Flores and Timor and two later separate human-mediated dispersals of domestic pig (Sus scrofa) through Island Southeast Asia into Oceania. Of the later dispersal routes, one is unequivocally associated with the Neolithic (Lapita) and later Polynesian migrations and links modern and archeological Javan, Sumatran, Wallacean, and Oceanic pigs with mainland Southeast Asian S. scrofa. Archeological and genetic evidence shows these pigs were certainly introduced to islands east of the Wallace Line, including New Guinea, and that so-called "wild" pigs within this region are most likely feral descendants of domestic pigs introduced by early agriculturalists. The other later pig dispersal links mainland East Asian pigs to western Micronesia, Taiwan, and the Philippines. These results provide important data with which to test current models for human dispersal in the region